Who's to say that a founder without a family will not posses realism, maturity, or seriousness. If anything, I would turn it around and say that being a founder and having a family is like trying to have your cake and eat it too, which is not realistic. Delayed gratification is one of the prevailing signs of maturity, and postponing settling down and starting a family until after establishing a business would be a clear example of it. And someone who consistently works very long hours is if anything serious.
We can argue these points all day, but the reality is, unless you can provide evidence that founders with families possess these attributes in measurably greater quantities, and with statistically significant higher probability of success, whether or not having a family is an asset or not in achieving success with a startup is purely subjective.
On the other hand, the number of available working hours, and how more work will result in greater likelihood of success is pretty objective. There may be diminishing returns as the number of hours increase, but at least up to a pretty high point, those returns will still be positive.
On the delayed gratification note, there are a couple of points. First, not everyone knows that they are going to be starting a business in the short-term when they have children. Second, there is a very real biological countdown in place for child-bearing and child-rearing. Our bodies do much better when the parents of the children are in their 20s and 30s. Many who delay their families find that they're limited by age-related implications. There are no such biological countdowns on entrepreneurship, and founders' experience, and therefore value, only increases as they age (until the point where dementia or other debilitating mental conditions become a serious possibility, but for most people that's well past retirement age). From a lifelong perspective, if you intend to have children, it's more intelligent to prioritize reproduction and delay your gratification for entrepreneurship.
Furthermore, family life teaches much more about delayed gratification than single 20-something life. If your argument is that entrepreneurs should show maturity through delayed gratification, the college kid really does not want to go up against the family man.
As to your point that the availability of excessive numbers of working hours and lack of work-life balance is superior, I think there are many who'd disagree. I don't feel compelled to cite a bunch of literature at the moment, but suffice it to say that slave-driving is not considered effective management, and workaholics are not considered healthy people.
There are important, valuable problems that simply aren't visible to the inexperienced kids that the current model wants working on startups. My own idea for a startup was the result of two decades of experience in the software industry and many years of seeing specific pain for myself and across the industry. I wouldn't have thought of it back in '94 when I was starting my career. And by the time I could see the problem (much less see a solution), I pretty much had the kids and the mortgage.
We can argue these points all day, but the reality is, unless you can provide evidence that founders with families possess these attributes in measurably greater quantities, and with statistically significant higher probability of success, whether or not having a family is an asset or not in achieving success with a startup is purely subjective.
On the other hand, the number of available working hours, and how more work will result in greater likelihood of success is pretty objective. There may be diminishing returns as the number of hours increase, but at least up to a pretty high point, those returns will still be positive.